1. Field of the Invention
This invention relates to a frame structure for housing panel plates such as printed circuit boards used in electrical and electronic devices and equipment, panels used in construction, and so forth. More particularly, the invention relates to a frame structure for housing panel plates that includes means for preventing the housed panel plates from breaking loose.
2. Description of the Prior Art
In order to prevent housed panel plates from breaking loose, housing frames have been provided with plate or rod shaped stops bolted in place, or with compression springs located at end portions to make the stops removable. Prior art stops have to be removed each time a panel plate is removed. As well as being inconvenient, the stops that have been removed can be lost, or it can be forgotten to affix the stops, allowing panel plates to fall and break.
To eliminate such drawbacks, JP-A-Sho 50-7068 discloses an apparatus, shown in FIG. 13, that prevents panel plates from coming out without involving removal of stops. As shown, the apparatus includes side plates 62, each of which is provided with a V-shaped guide groove 63. Each of the ends 65 of a stop rod 64 fits into the groove 63. A spring 66 is provided so that each end 65 of the stop rod 64 can stop at either one end of the V-shaped groove 63. The spring 66 urges the stop rod 64 towards the lower end of the groove, or towards the horizontal portion. When the stop rod 64 is at the lower end of the guide groove 63, the rod 64 abuts against the housed printed circuit boards 61, preventing the boards 61 from coming out of the apparatus. The boards 61 can be removed by moving the stop rod 64, against the tension of the spring 66, to the horizontal portion of the guide groove 63. The above configuration eliminates having to remove a stop rod each time a board was to be removed or inserted.
In the case of the above apparatus, however, it can readily happen that a non-uniform application of force to move the stop rod can result in a failure to keep the stop rod horizontal during the operation. A further drawback is that the size of the apparatus is increased by the need to provide enough space to provide the side plates with the V-shaped grooves and the springs. Also, since the springs project beyond the side plates, the springs are prone to being moved and dislodged by outside force.
Therefore, an object of the present invention is to provide a frame structure for housing panel plates that includes stop means for retaining the housed panel plates that can be moved for operation smoothly and securely.